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. 2020 Aug 17;190(2):288–294. doi: 10.1093/aje/kwaa170

Table 2.

Rate Ratios of Encephalopathy, Unspecified Dementia, and Combined Encephalopathy and Unspecified Dementia According to Cumulative Styrene Exposure Accrued During Different Exposure Time Periods Among 72,465 Workers of the Danish Reinforced Plastics Industry, 1977–2011

Encephalopathy Unspecified Dementia Combined Encephalopathy and Unspecified Dementia
Exposure Period and Cumulative Styrene Exposure Person-Years Cases RR a 95% CI Cases RR a 95% CI Cases RR a 95% CI
<15 years prior, mg/m3-years
 0 635,123 93 1.00 466 1.00 559 1.00
 <26 430,989 46 1.36 0.94, 1.98 56 0.89 0.66, 1.21 102 1.07 0.85, 1.34
 ≥26 430,482 89 1.67 1.17, 2.37 43 0.65 0.45, 0.94 132 1.09 0.86, 1.39
  P for linear trend <0.01 0.03 0.43
15–29 years prior, mg/m3-years
 0 872,793 117 1.00 273 1.00 390 1.00
 <46 311,893 31 0.61 0.41, 0.93 125 1.01 0.81, 1.25 156 0.81 0.67, 0.98
 ≥46 311,908 80 1.42 1.04, 1.93 167 0.82 0.67, 1.01 247 0.87 0.73, 1.03
  P for linear trend 0.05 0.07 0.08
≥30 years prior, mg/m3-years
 0 1,305,496 201 1.00 296 1.00 497 1.00
 <45 95,303 13 0.75 0.41, 1.37 106 1.08 0.85, 1.38 119 1.10 0.88, 1.38
 ≥45 95,795 14 0.80 0.45, 1.44 163 1.19 0.95, 1.48 177 1.21 0.98, 1.49
  P for linear trend 0.35 0.13 0.07

Abbreviations: CI, confidence interval; RR, rate ratio.

a Adjusted for age, calendar year, sex, level of education, hospitalizations related to chronic obstructive pulmonary disease, alcohol-related hospitalizations, and employment status.